Cope, Proc. Acad. Sci. Phil., p. 16, 1875.
Cope, Geol. Surv. Ohio, II, pt. II, p. 387, 1875.
Type: Hyphasma lævis Cope.
"Vertebræ osseous, the posterior dorsals, and probably the caudals, furnished with fan-like neural spines; limbs unknown—(?) wanting. Thoracic shields present. Ventral armature, consisting of rhomboidal scuta, forming packed rows arranged in chevrons, directed backwards, on top of which are the usual rod-like scales arranged in packed chevrons, with the angle directed forward.
"The general appearance of the type of this genus is that of a Ptyonius, but the ventral armature is different from anything observed in the known genera of this group. The larger external scuta are like those of the species of Colosteus (Sauropleura) , but their series have a different direction. The inner chevrons are those of many other genera" ([123]).
Hyphasma lævis Cope.
Cope, Proc. Acad. Sci. Phil., p. 16, 1875.
Cope, Geol. Surv. Ohio., 11, pt. II, p. 387, pl. 37, fig. 4, 1875.